In general, an aircraft nacelle has a structure comprising an air intake structure, a middle structure, and a downstream section. The term “downstream” here refers to the direction corresponding to the direction of the cold air flow penetrating the turbojet engine. The term “upstream” designates the opposite direction.
The air intake structure is situated upstream of the turbojet engine used to propel the aircraft. Downstream of the air intake structure, the middle structure is intended to surround a fan of the turbojet engine. Still further downstream is the downstream section generally housing thrust reverser means intended to surround the combustion chamber of the turbojet engine. The nacelle ends with a jet nozzle whereof the outlet is situated downstream of the turbojet engine.
The air intake structure comprises, on one hand, an air intake lip and, on the other hand, a downstream structure on which the lip is fastened. The air intake lip is adapted to allow optimal air collection towards the turbojet engine of the air necessary to power the fan and the internal compressors of the turbojet engine. The downstream structure is intended to suitably channel the air towards the vanes of the fan. This downstream structure generally includes an outer panel and an inner panel. The inner panel includes an acoustic shroud making it possible to attenuate the noise generated by the turbojet engine as well as the vibrations of the structures. The downstream structure and the air intake lip are fastened upstream of a casing of the fan belonging to the middle structure of the nacelle.
Depending on the relative temperature and humidity conditions on the ground or in flight, ice may form on the profile of the lip, in particular at the inner profile. This ice formation can be dangerous for the mechanical operation of the fixed and rotary parts of the turbojet engine and can cause a decrease in performance. Deicing systems for this part of the air intake lip have therefore been developed to resolve this problem. Examples include documents U.S. Pat. No. 4, 688,757 and EP 1 495 963 in particular.
It is known to perform maintenance operations on this equipment housed inside the air intake structure by sliding the outer panel 40 incorporating the air intake lip upstream of the middle structure 5 by guide means 15 (see FIG. 1). Generally, such guide means 15 assume the form of a system of rails.
However, the guide means 15, in particular the rails, tend to deform during the transition from the closing position to the opening position (see FIG. 2). “Opening position” here refers to the configuration in which the air intake structure is translated in the upstream direction. The opening position corresponds to a configuration where the aircraft is on the ground for maintenance. Conversely, “closing position” here refers to the configuration in which the air intake lip is attached to the upstream end of the inner panel(s). The closing position corresponds to a configuration in which the aircraft is able to fly.
In the opening position, the guide means, in particular the system of rails, bears the mass of the moving assembly, which is generally greater than the bending strength of the rails. As a result, as shown in FIG. 2, there is a deformation of the guide means 15 that amounts, in the case of rail systems, to bending thereof relative to their axis. The deformation can also be accentuated by external factors such as the wind. Such a deformation makes the opening maneuver more difficult.
Moreover, there is a risk of the upstream end of the rails being used as a ladder rung by an operator, further accentuating the deformation.
One aim of the present invention is therefore to provide a nacelle limiting the deformation of the guide means.